Valley step

The transportation of gravels, erosion and sedimentation processes in the streams lead to the formation of sequences of flat valley bottoms and gorges.

Similar steps are formed when moving sheets of ice merge into glacial streams, which can intensify surface scouring of the rocks (exaration).

In the interior of mountain ranges, these valleys dictate the structure of settlements, and may result in isolated communities that are difficult to access.

Borderline cases are, for example, cirques, which typically form basins in which there is often a lake which either drains periodically over the valley threshold or seeps entirely into the subsoil.

These can then also create a very characteristic structure of a river course in its lower reaches on the broad plains and form a significant obstacle to navigation.